The objective of this experimental study was to determine the kinetics and equilibrium sorption of CrVI in soils collected from Hengshui City of Hebei Province, China, based on batch experiments. The main concentration for this paper is on the effect of soil pH, solute concentration and ionic strength as the variable factors in the sorption of CrVI in soils and the assessment of their implications to the environment. Atomic Absorption Spectrophotometer AAS was used for CrIII analysis; UV-VIS Spectrophotometer for quantification of CrVI in soil samples and determination of electrical conductivity and temperature of the soil samples; and Automatic Laser Particle Size Analyzer LS230 for the determination of soil physical characteristics. Results from this study show that adsorption and reduction are major reactions accounting for removal of CrVI from soil solution. It is concluded that chemical reactions such as reduction, strongly influence CrVI mobility in soil. Adsorption kinetics experiments indicated that CrVI removal from soil solution increases with increasing solute concentration, with decreasing pH and with decreasing ionic strength. Adsorption reactions reached equilibrium within 12 hours in batch reactors. Increasing background electrolyte concentration KCI decreases CrVI adsorption on soil. The CrVI adsorption isotherm for this soils conforms well to the Langmuir isotherm at constant pH. Two CrVI adsorption parameters: the maximum sorption capacity Qo and Langmuir adsorption constant KL, were determined as 1.0135 × 10-4 mol-g and 0.0622 mg-L, respectively. The reduction of CrVI into less toxic CrIII, means reduction of significant environmental problems. Finally, this study advises relevant environmental governing authorities to observeperiodic monitoring of the status of CrVI in soils.

KEYWORDS

Soil, Hexavalent Chromium, Reduction, Adsorption

Cite this paper

Kwikima, M. and Lema, M. 2017 Sorption Characteristics of Hexavalent Chromium in the Soil Based on Batch Experiment and Their Implications to the Environment. Journal of Geoscience and Environment Protection, 5, 152-164. doi: 10.4236-gep.2017.53011.